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Archive by category: Biodiversity and Ecology

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Madagascar: how to save a forest

Anjali Nayar, an International Development Research Centre fellow at Nature, recently visited a pioneering project in Madagascar that's aiming to protect one of the country's few remaining forests. About 90% of the species in Madagascar's rainforests are found nowhere else on Earth, but efforts to save the island nation's forests are about more than conserving biodiversity.

It's hoped that projects like this will provide a model for efforts to reduce greenhouse gas emissions from deforestation. Under a proposal, known as reducing emissions from deforestation and forest degradation (REDD), wealthy nations could meet their emissions targets in part by buying carbon credits from developing countries such as Madagascar. REDD is one of the topics up for discussion at the UN climate-change conference in Copenhagen this December. Countries will negotiate whether REDD should be included in the global climate deal that takes over from the Kyoto Protocol.

But as Anjali reports, to be successful these projects must overcome the poverty and political upheaval common to most developing countries. Read Anjali's full report here. Or see a slideshow video version, here.

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Consumer boom in hotter seas

Mysis2kils.jpgAs warming starts to shake up marine food webs, ecologists say it may give an unexpected boost to some fisheries - but also make them more precarious.

This is one of the implications of a new experimental study in PloS Biology that takes a panoramic point of view. Rather than tackling complex food webs species by species, the authors look at how warming affects growth and metabolism across the board within the broad groups of organisms at the base of the web.

Mary O’Connor of the University of North Carolina, Chapel Hill, and colleagues turned up temperatures in outdoor containers holding phytoplankton, the ocean’s primary producers, and bacteria and zooplankton, the smallest consumers. Warming of two to six degrees drove up the productivity of phytoplankton, as expected. But consumers increased their growth even more. Zooplankton retain only about 10% of the biomass they eat, so total biomass declined as the hungry hordes munched on the phytoplankton.

Zooplankton are fish food. O’Connor tells New Scientist, "The effect could be translated up the food chain" to a gain in fisheries, but “that top-heavy food web structure could be less stable, and crash all together." The group found that the consumer boom was much greater when nutrients were added, so they suggest that food webs in nutrient-poor waters - such as the ocean surface - may be more resilient to climate change.

The study is timely: NOAA’s National Climatic Data Center recently announced that world ocean temperatures were the hottest on record last month. The temperatures beat the 20th-century average by nearly 0.6 degrees Celsius. According to AP, meteorologists are attributing the record high to a combination of global warming trends, an El Nino phase just getting started, and other natural variation. Apparently, an unusual and unexplained weather pattern this summer is concentrating warmth over the ocean while land surfaces stay cooler.

And this won’t be a brief blip in sea temperatures:

Breaking heat records in water is more ominous as a sign of global warming than breaking temperature marks on land, because water takes longer to heat up and does not cool off as easily as land.

"This warm water we're seeing doesn't just disappear next year; it'll be around for a long time," said climate scientist Andrew Weaver of the University of Victoria in British Columbia.

Anna Barnett

Image: Mysis zooplankton / Uwe Kils, Creative Commons license

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When money grows on trees

climate.2009.78-i1.jpgIn this year’s series of UN climate talks - the latest of which took place last week in Bonn - one of the issues negotiators are sinking their teeth into is a source of greenhouse gases that has previously been sidestepped. Chopping and burning trees causes an estimated one-fifth of global emissions, and slowing down deforestation could be the cheapest and quickest way to keep a substantial load of gas out of the atmosphere. With this in mind, the Bali meeting in 2007 called for a decision on forests to be made by the time the 2009 talks wrap up in Copenhagen this December.

But deciding to do something about it and agreeing on what needs to be done are two very different matters, as Mark Schrope writes in a feature on Nature Reports Climate Change this week. He explains:


Some of issues raised are rooted in serious ethical and environmental concerns, such as how to protect indigenous people and ensure compliance. But much of what was being mulled over boils down to money: adequately addressing deforestation will require a new flow of billions of dollars from developed to developing nations. Developing countries are scrambling to position themselves to receive as much as possible, while developed nations are doing their best to ensure they get what they want from their investments. The result is a complex debate that is likely to grow more heated as countries move from stating their positions to settling on an agreement that everyone can live with beyond December.

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How to heat a forest… or at least, a part of one

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Sure, accidentally heating the planet has been pretty easy. But try intentionally heating a plot of forest, and you get a whole other story.

In this week’s Nature, we take a brief look at a series of new experiments to test how warmer temperatures will change the composition of forests in different regions of the United States. Will forests begin to sprout above the tree line in the Colorado Rocky Mountains? Will oaks sweep northwards, deeper into the boreal forests of the northern United States and Canada?

Unfortunately, reliably and evenly heating a stand of grown trees to a set number of degrees above ambient temperature turns out to be pretty difficult to do. For now, these projects are limited to seedlings which will outgrow their heaters within a few years. Such studies are valuable in their own right – seedlings lack the extensive root networks that could help them survive a hot, dry summer, and are therefore a weak link in the chain of forest succession. Still, wouldn’t it be great if we could see the effects of climate change on the grown-ups, too?

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Visualizing the assisted migration argument

Formerly a taboo topic among conservationists, ‘assisted migration’ or ‘managed relocation’ – literally moving sensitive species to new habitats in order to save them - has recently started to come in for serious consideration. A paper out in PNAS this week offers a quick and innovative way to evaluate candidate species with new visual tools.

Some of the paper’s authors, including Stephen Schneider of Stanford, California and Jessica Hellman of Notre Dame, Indiana were part of a meeting last year on how to make such decisions, which we covered in a news feature at Nature Reports Climate Change.

The authors analyze the possibilities for three candidate species:
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Image courtesy of PNAS.

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Obama backs Bush on polar bear

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Despite pressure from many environmentalists, the Obama administration upheld a Bush administration rule limiting the regulatory impact of last year's decision to list the polar bear as a threatened species.

The rule would essentially prevent the Endangered Species Act from becoming a venue for arguments about greenhouse gas emissions. And the logic is simple enough: Bear biologists hopefully have better things to do than analyze greenhouse gases from, say, a cement plant in Georgia, even if emissions from that plant contribute to global warming and the retreat of sea ice, which ultimately translates into hungry bears.

"We already are doing everything we can to protect the polar bear," US Interior Secretary Ken Salazar told reporters Friday. "The Endangered Species Act, however, is not in my view the proper mechanism for controlling our nation’s carbon emissions."

Continue reading 'Obama backs Bush on polar bear' on Nature's The Great Beyond blog

Image courtesy of the U.S. Fish and Wildlife Service

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Birds face longer migrations due to climate change

sylvia.jpgClimate change could force birds to migrate hundreds of extra miles, according to new research. The extra distance might even be deadly.

Modelling by Stephen Willis, of Durham University, and his colleagues shows that the breeding ranges of Sylvia warblers will shift consistently north as the Earth warms. Non-breeding ranges showed no consistent directional shift, meaning longer migrations.

“From 2071 to 2100, nine out of the 17 species we looked at are projected to face longer migrations, particularly birds that cross the Sahara desert,” says Willis (press release). “Our findings show that marathon migrations for some birds are set to become even longer journeys. ... The added distance is a considerable threat.”

According to the team’s paper in Journal of Biogeography, trans-Saharan migrants face an average extra flight of 413 km. The researchers write that the challenge facing many species is “unprecedented”.

Continue reading 'Birds face longer migrations due to climate change' on Nature's The Great Beyond blog.



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Tropical forests: From sink to source?

The Earth’s large forests take up substantially more atmospheric carbon dioxide through photosynthesis than they release back to the atmosphere through respiration. Thus acting as a carbon ‘sink’, they (and the oceans) are our closest natural allies in the fight against climate change.

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But many forests are at threat - not only from logging and clearing, but from climate change itself.

Take drought. How will mature tropical rain forests respond to dryer conditions, which some climate models suggest might be ahead in the not-so-distant future?

The 2005 drought in the Amazon basin gave scientists an opportunity to find out. What they saw is not particularly heartening: Prolonged dryness has apparently turned some affected areas of the Amazon from a carbon sink to a carbon source, a team led by Oliver Phillips of Leeds University in Britain reports in Science today (Abstract here).

Patches subjected to a 100-milimetre decrease in rainfall released on average 5.3 tonnes of carbon per hectare – around 9 times the amount undisturbed tropical forests take up, on average, per year. Basin-wide, between 1.2-1.6 billion tonnes of carbon were released during the 2005 drought, the team estimates.

Over at Nature News, I’ve put together a little briefing on what we know and what we don’t know about the tropical carbon sink.

Quirin Schiermeier

Image: Punchstock

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Wanted: Citizen climate scientists (shared Nobel Prize not guaranteed)

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Uncle Sam wants your observations of flowering and fruiting American plants. A new national ‘citizen science’ program is starting up in the US that asks volunteers to send in data on the seasonal cycles, or phenology, of local plants - information that researchers can use to track shifts caused by climate change and other factors. Animal-lovers can start contributing data next year. Running the effort is the USA-National Phenology Network, a consortium of universities, nonprofits, and government agencies - notably the US Geological Survey, who cover the new program on their latest podcast.

Says the press release:

Among other uses, data collected by USA-NPN will help resource managers predict wildfires and pollen production, detect and control invasive species, monitor droughts, and assess the vulnerability of various plant and animal species to climate change.

Continue reading "Wanted: Citizen climate scientists (shared Nobel Prize not guaranteed)" »

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Picture post: 'thermal microhabitats'

Cross-posted from The Great Beyond

At a talk yesterday in Washington, plant ecologist Christian Körner showed just how variable temperatures can be in the mountains, even between patches of land that are close together.

This could offer possible escape routes for animals impacted by global warming, as potentially they wouldn’t have to move as far as people think to reach a cooler place to live, he says.

Korner image.JPG

Korner’s lab explains the image as follows:

Using a high resolution thermal imaging camera, this picture illustrates the large variation of temperatures in an alpine landscape at 2500m elevation in the Swiss Alps. Topography and plant cover engineer massive deviations from ambient conditions when the sun is out, permitting plants and animals to thrive in an otherwise cold world. By short distance migration plants and animals can select thermal microhabitats that would otherwise be hundreds of meters of elevation apart.

The image is based on unpublished data by Sebastian Leuzinger and Christian Körner, of the University of Basel in Switzerland and is used courtesy of Körner, who was speaking at the ‘Twenty-First Century Ecosystems: Systemic Risk and the Public Good’ symposium.

Roberta Kwok

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Ocean acidification disorients fish, riles up scientists

clownfish.jpgI may need to start a file for ‘ocean impacts we hadn’t thought of’. First there was the projection that the seas will get noisier as a result of ocean acidification, which whale conservation groups were running with at a UN conference in December. Now researchers report in PNAS that ocean acidification may make fish larvae lose the sense of smell they use to find a home.

Most coastal marine species are swept out to sea during their larval stage and have to find their way to a habitat they can settle down in. Orange clownfish - yes, that’s the famously lost fish from Finding Nemo - must get back to reefs, often ending up in the same ones where they hatched. Philip Munday and Danielle Dixson of James Cook University in Australia have been studying olfactory cues the clownfish may follow.

But they and their colleagues report that clownfish larvae reared in aquariums at pHs of 7.8 and 7.6 don’t respond to smell tests the same way as control fish. These pHs are low compared to the 8.15 the fish live with today, but a business-as-usual rise in carbon dioxide emissions could take the ocean to 7.8 by 2100 and 7.6 in the following century.

Larvae reared at pH 7.8 favour the pungent smell of a swamp tree that clownfish normally avoid. They also fail to discriminate between the smells of their parents and other adults, suggesting that acid-addled Nemos might end up inbreeding more often. The pH-7.6-reared fish don’t swim toward any of the tested scents, suggesting they've stopped smelling altogether.

It’s not just clownfish that smell their way home. If acid damages fish's olfactory capabilities the researchers say, many other coastal marine species could be affected.

One question the paper doesn’t take up is whether an ocean pH of 7.6 would leave any reefs for clownfish to come back to. The danger to reefs, and other better-known impacts of acidification, have meanwhile been highlighted in a declaration by 155 ocean scientists from 26 countries - and they want action.

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Climate change hits loveable lemmings

Cross posted from the Great Beyond

lemming top.jpgLet us get one thing clear right at the start: lemmings do not commit mass suicide by leaping off cliffs into the sea. However, their populations do undergo massive size fluctuations, leading to mass migrations where the cute critters may go swimming to find new food sources.

At least, they used to undergo massive population explosions. In a paper published this week in Nature a group of researchers analyse the absence of such events since 1994. The culprit, you guessed it, is climate change.

Nils Stenseth and colleagues show that changes in winter weather and snow go hand-in-hand with changes in Lemmus lemmus populations. They further show that when the regular explosion of lemming numbers doesn’t occur predators such as foxes switch their attention to other species, leading to knock-on effects throughout the eco-system.

“A relatively small effect on one particular species is having a broad effect on the system,” Stenseth, a researcher at the University of Oslo, told Reuters.

lemming angry.jpgIn a News and Views piece analysing the research, Tim Coulson and Aurelio Malo, of Imperial College London, explain that lemmings like to scurry about in a gap that warm ground melts between it and the snow layer above it. This so-called subnivean space is relatively warm and keeps the rodents safe from things that would like to eat them.

What Stenseth and colleagues found was that climate change seems to have eliminated the subnivean space and, worse, created a sheet of ice over the moss on which lemmings like to nibble.

“The critical reader will complain that the story is based on correlations. Although this is true, it is often the only way to study populations and the consequences of changing climate for ecosystems,” write Coulson and Malo. “The collection of detailed long-term data on the dynamics of free-living populations of animals and plants rarely attracts the same excitement as genomics or particle physics, yet such data are vital in characterizing the consequences of climate change for the natural world on which we depend.”

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Pre-empting climate change extinctions

IUCN.JPGOne of the world's largest conservation organizations is getting into the business of predicting which species could suffer most from future climate change - even before the damage begins to show.

The International Union for Conservation of Nature (IUCN) is known for its annual Red List, which tracks species populations worldwide over time and nominates those most in danger of extinction. But in a chapter of this year's Red List report, it released early work on a new roster: species susceptible to a climate-induced snuffout in the years ahead.

The new project may facilitate what is being dubbed 'pre-emptive conservation'. Emma Marris reports today on Nature Reports Climate Change:

The data [on climate susceptibility] may someday be integrated into the Red List itself, so that researchers who map hotspots of threatened species or otherwise model biodiversity can include future climate-change-related threats, even if species appear to be in the pink of health. Parks can be planned, corridors built, and more aggressive measures, such as so-called 'assisted migration', can be considered before population numbers begin to decline — a pre-emptive strike against extinction.

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It’s conservation – but not as we know it

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This week on Nature Reports Climate Change, we have a news feature on a topic that has been considered something of a conservation taboo: assisted migration – in other words manually relocating species that are under threat of extinction from climate change.

There’s been a spate of coverage on assisted migration the last year, but as Emma Marris reports, experts are now starting to give serious consideration to how it might work in reality.

Meeting in Milwaukee, Wisconsin from August 1 to 3 ahead of this year’s Ecological Society of America was a group of scientists, lawyers, land managers, economists and ethicists, some of whom feel that relocating species would most likely be a disaster. But it looks like even those opposed to the idea are concerned enough to consider it an option.

Ok, so no-one is really suggesting we move polar bears to the Antarctic (I just liked the cartoon)! More likely is shifting the quino checkerspot butterfly several hundred kilometers north.

But with climate change impacting biological systems throughout the globe, the reality is that many species may have to adapt to climate change in situ or say sayonara as part of the Earth’s sixth mass extinction. And for those that could up and leave to a better place if they were not hemmed in by human barriers, giving them a helping hand could make all the difference.

But as Emma details in her news feature, proposals to relocate species are likely to meet some significant barriers - and not just of the physical kind.

Continue reading "It’s conservation – but not as we know it " »

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Biodiversity vs. carbon sinks - an Oregon tale

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When I tell people I grew up in Oregon, they usually have one of two reactions. Some faces tense as they try to place the state on their mental US map somewhere around Nevada (actually it’s on the Pacific coast, above California). Others light up because they’re about to say, “Oh, it’s beautiful there!”

If you don’t mind drizzling rain or hay fever - so much grass seed is grown in my native Willamette Valley that in summer the local paper prints the pollen count next to the weather forecast - it really can be pretty nice. There's a new PNAS article straight out of that valley, balancing the benefits of conserving its various lovely natural landscapes - wetlands, prairie, oak savannah, and conifer forests.

Wetlands.jpgManaging land use to encourage these ecosystems can boost biodiversity and create carbon sinks that help mitigate climate change.

No, strike that: it can boost biodiversity or create sinks.

Continue reading "Biodiversity vs. carbon sinks - an Oregon tale" »

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A tribute to the trees

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For all tree huggers out there, this week’s Science is dedicated to ‘forests in flux’, paying tribute to the trees and their contribution to the greater good. A special collection of articles in print, with complementary and online material, examines the fate of the world’s forests, in the face of climate change and an escalating human population.

If it’s been a while since you’ve had the chance to appreciate the languid leafiness of forest foliage, check out the online video. Or for those of you hoping for a more ‘hands on’ experience, there’s a whole section of Science Careers dedicated to opportunities in forest ecology.

There’s lots of serious science, with six Perspectives and one Review by researchers from all over the globe who give their tuppence worth on what’s needed to better understand forests and manage them properly.

Of particular relevance to discussions on how forests can mitigate global warming, Lera Miles and Valerie Kapos have a Perspective highlighting the risks involved in proposed schemes such as REDD (reduced emissions from deforestation and forest degradation) and how to minimize them. Also on this topic, Josep Canadell and Michael Raupach write on what science currently tells us is the best way to manage forests for sequestering carbon.

Drew Purves and Stephen Pacala discuss how forest dynamics remain one of the largest uncertainties in predicting future climate change and detail some of the efforts underway to improve their representation in models. Or for a really solid review of how forests affect climate change, check out Gordan Bonan’s piece here.

Or if that seems like a lot of tree pulp to get through, here are some interesting stats from the issue:

Forests cover ~42 million km2 in tropical, temperate, and boreal lands, and cover ~30% of the land surface

They store ~45% of terrestrial carbon and account for ~50% of terrestrial net primary production.

Forests hold more than double the amount of carbon in the atmosphere.

Carbon uptake by forests in the 1990s contributed to ~33% of anthropogenic carbon emission from fossil fuel and landuse change.

Olive Heffernan

Image: Plantations of Pinus radiata and Eucalyptus nitens in Gippsland (Victoria, Australia); courtesy of Michael Ryan.

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Immediate impacts of a warming world

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Nearly 30,000 phenomena in the natural world - from the timing of plant flowering to the rate of ice melting - are being influenced by human-induced global warming, according to the first study to formally link trends in biological and physical systems to rising greenhouse gas emissions.

Led by Cynthia Rosenzweig of NASA's Goddard Institute for Space Studies in New York, the analysis, published in this week's Nature, brings together data from numerous different studies stretching back to 1970 to gain a big picture view of how climate change is impacting the planet.

Although the latest report from the Intergovernmental Panel on Climate Change (IPCC) concluded that human-induced climate warming is "likely" to have had a discernible effect on physical and biological systems, attributing such changes in natural systems to specific causes in notoriously difficult, as highlighted in the related News and Views article by Francis Zweirs and Gabriele Hegerl, both IPCC panelists.

Rosenzweig and collaborators made this link first by mapping changes in global average suface temperature between 1970 and 2004. They then looked at whether changes in natural phenomena in each region were consistent with warming or inconsistent with warming e.g. earlier blooming of flowers would be expected in a warmer climate.

In more than 90% of cases where there was a trend, it was consistent with the predicted effects of a warming world. As Emma Marris points out in an online news story, the bulk of the data come from Europe and several hundred more come from elsewhere in the world, but Africa, Australia and Latin America are poorly represented.

Olive Heffernan

Image credit: David Inouye

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